We are requesting funds to purchase an instrument (KinExA) with the ability to sensitively and precisely measure binding kinetics from the millimolar to picomolar ranges and to quantify femptomolar concentrations of molecules of interest in complex solutions. These instruments will be used to identify, quantify and characterize small molecules and proteins that bind to biological targets of interest, which can then serve as starting points for drug discovery and development. There are no machines with the same capabilities available at the University of Texas at Austin or nearby campuses. UT does have one BIAcore 3000, able to measure binding kinetics to an immobilized ligand with less sensitivity, which is highly valued and receives very heavy use, such that it is practically unavailable to most users. The protein core facility owns a BIAcore 1000 which is available to most users, but has outlived its useful lifetime (produced circa 1990) and no longer produces reliable data. Regardless, these BIAcore machines do not possess several key desired capabilities: the ability to measure binding kinetics in solution, the ability to measure equilibrium dissociation constants as low as picomolar or as high as millimolar, or the ability to measure concentrations of molecules of interest when present at parts per trillion concentrations. The addition of a KinExA would therefore serve a unique purpose at UT Austin. The new equipment would be placed in the Institute for Molecular and Cellular Biology (ICMB) Protein Core Facility at UT and be available to the entire UT community. The ICMB has already established the space, staff, and recharge policies to maintain this equipment. The purchase of this instrument has broad support;the major and minor users listed in this proposal come from two institutions, three colleges and six departments, and their collective research interests address three NIH-funded themes: (1) drug discovery and development, (2) effects of water quality on human health and (3) basic mechanisms of carcinogenesis. Addition of these instruments will introduce radically new capabilities at the UT campus for drug discovery technologies and developing therapies in a variety of disease areas. PUBLIC HEALTH RELEVANCE: The KinExA instrument for which we are requesting funds represents a new, highly sensitive and rapid method for identifying and measuring the concentration of molecules with biological activity. These molecules can be used to interrogate basic biological phenomena or comprise new therapeutics for a wide variety of human diseases.